1. Field of the Invention
This invention relates to a switch cabinet with a rectangular frame support, the front and rear sides of the switch cabinet are sealable by means of two casing doors hinged on the frame support, or by means of a casing door hinged on the front frame support and a rear wall attached in a detachable manner on the rear frame support. The remaining sides of the switch cabinet are covered by means of covering plates which can be attached in a detachable manner on the frame support.
2. Description of the Prior Art
Such a switch cabinet is not protected against electromagnetic radiation, since the cover plates, rear walls and casing doors, which are preferably treated on their surfaces have no adequate electrically conductive connection with the frame support. This transition is often made even worse by the fact that the cover plates, rear walls and casing doors are connected to the frame support by fastening screws, and supported on the frame support outside the attachment points by means of sealing strips.
German Patent Publication DE-OS No. 34 31 712 teaches electronic devices or a framework with plug-in units which may be shielded in an HF-impermeable manner by inverting a metal hood unit over the device or the framework, placing the device or the framework on a base plate, and then connecting the hood unit and the base plate in an electrically conductive manner. To facilitate access to the devices or the framework, one wall of the hood unit may be provided with a door, which is connected with the hood unit in the known manner by means of known types of contact strips.
These known types of shielding hoods are not suited for switch cabinets of the type stated, which already has one or two casing doors. The hood unit would have to accommodate, in addition, one or two further doors which are shielded against HF, which would considerably increase the expense of shielding the switch cabinet. A closed hood unit which may be removable from the base plate is not satisfactory, since the space in which the switch cabinet is installed often does not provide the necessary height for removing the hood unit. In a switch cabinet requiring frequent access to built-in electrical devices and equipment, such an arrangement is entirely unsatisfactory.